Research On Foundation Pit Supporting Structure Of Subway Station

Subway is one of the major city people travel the way to ease the traffic pressure on the ground,but with the large increase in the number of ground vehicles,the Metro daily traffic pressure burden is also increasing,size of excavation of subway station is more and more toward the depth,width,the direction of development.This paper briefly summarizes the development status of foundation pit engineering,and summarizes several main excavation supporting types,including slope excavation,underground continuous wall,bored pile,cast-in-place pile,reinforced cement soil wall,steel sheet pile and composite soil nailing wall and the corresponding support and external support.Introduce the structure features and scope of application.The subway station deep foundation selected supporting form need to consider the proposed site engineering geological and hydrogeological conditions,the design of the foundation pit size,precipitation and groundwater conditions as well as the surrounding environment,the requirement of controlling the deformation of the pit wall,which are selected according to the actual situation,in the subway station in the construction process,the following general selection of support form:slope excavation and shotcrete support,reinforced concrete sheet pile,underground continuous wall and bored pile additional steel support or cable.Through the comparative analysis of the advantages and disadvantages of various structures,according to the engineering geological and hydrogeological conditions of the pit(soil soft soil and the proposed site is roughly water rich medium),through fuzzy multi-objective decision-making theory,selection of bored pile and steel support this form of support,software support structural preliminary design using deep for the design of foundation pit,using the finite element software MIDAS/GTS model was used to simulate the excavation process and the calculation results are compared with the preliminary design,the optimizing result is safe and reasonable.According to the engineering example of the pile and steel support are analyzed,according to the construction site and the design results will be divided into several cases of soil around the foundation pit excavation simulation in the settlement process.